Anti-spin device



Sept. 28, 196 E. w. THOMPSON ANTI-SPIN DEVICE Filed Jan. 29, 1964 INVENTOR. fml l M Thompson BY 23 1. X WZ United States Patent 3,208,345 ANTI-SPIN DEVICE Emil W. Thompson, Succasunna, N.J., assignor to the United States of America as represented by the Secretary of the Army Filed Jan. 29, 1964, Ser. No. 341,137

3 Claims. (Cl. 89-1) (Granted under Title 35, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to an anti-spin device and more particularly to a device for obtaining a reduction in the spin rate of a projectile which is fired from a rifle tube and which obturates by means of an expanding plate which engages the rifling of the weapon barrel.

Present day ammunition includes special type warheads and these warheads can withstand but limited spin rates and therefore cannot eflectively be used in conventional type weapons which have rifled barrels.

The present invention is designed to overcome this disadvantage by providing an expander disc which will, upon firing of the projectile, move forward to expand the obturator to engage the rifling of the weapon tube.

It is a prime object of this invention to enable special type projectiles having a limited spin rate to be fired from a conventional rifled gun barrel.

It is another object of this invention to provide an expander disc which moves forward, upon firing of the projectile to expand the obturating element diametrically to engage the rifling of the weapon barrel.

It is a final object of this invention to provide an obturator which eliminates the usual keyways therefrom, thus providing greater simplicity and greater economy of construction.

The specific nature of the invention as well as other objects and advantages thereof, will clearly appear from a description of a preferred embodiment as shown in the accompanying drawing in which:

FIG. 1 is a partial cross sectional view of the lower portion of a rifled barrel mortar and showing a projectile therein having an anti-spin device thereon constructed in accordance with the present invention;

FIG. 2 is a fragmentary sectional view of the anti-spin device after firing of the mortar; and

FIG. 3 is an elevational view of a spigot type projectile having the anti-spin device of the invention.

Referring more particularly to the drawing, there is illustrated in FIG. 1, the lower portion of a trench mortar in section. The showing of a trench mortar is by way of example only, since the invention is intended for use in other weapons having a rifled barrel such as a howitzer, etc., and the weapon is represented generally by reference character 1.

The mortar is of the conventional type and includes a barrel or tube 2, a base 3, a firing element 4 and rifling 5. The firing element may be electrically operated if desired.

The projectile, indicated generally by 12, as shown in FIG. 1 is of the spigot type and is illustrated completely in FIG. 3. It consists of a spigot tube 6, a warhead 7, a combustible cartridge case 8 and the anti-spin device of the invention designated generally by 9. Electrical lead wires for electrical firing, if desired, are indicated by 10.

The anti-spin device of the invention is constructed as follows: spigot tube 6 is provided with a detachable end cap 11. A first sleeve 13 extends rearwardly from the spigot tube 6 and is provided with holes 14. A strainer 15 is fixed on sleeve 13 at its rearward end and is provided with radial ports 16 mating with holes 14, thus 3,Z@8,345 Patented fiept. 28, 1965 providing communication between combustible cartridge 8 and spigot tube 6. Cartridge 8 contains a propellant 17. A detonator 18 is attached to strainer 15.

The method and means for firing the propellant form no part of this invention and are shown only schematically, since any expedient method and means may be employed dependent upon the type projectile to which the anti-spin device is to be applied.

A second sleeve 20 extends forwardly from strainer 15 and encircles the first sleeve 13 and is threadably engaged in cap 11.

A Teflon antifriction slip disc 21 is rotatably mounted on sleeve 13 and abuts cap 11 and a third sleeve 22, integral with disc 21 extends rearwardly therefrom and encircles the second sleeve 20.

A rotating obturating disc 23 is slidably mounted on the third sleeve 22. Disc 23 is provided with an annular, rearwardly extending flange 24 which is beveled as at 25.

An expander plate 26 is slidable on the third sleeve 22 and is provided with a bevel 27 to mate with the bevel 25 on flange 24.

Operation FIG. 2 shows the device upon firing of the projectile in the mortar tube 2.

Before firing, the expander plate 26 rests against the outer edge of rotating disc flange 24 as shown in FIG. 1 and in this position, the rotating disc is below the rifling 5 of the mortar tube 2. When the combustible cartridge 8 is fired, the gases generated force the expander plate 26 against the rotating disc 23 and its beveled edge 27 rides under the beveled edge 25 of the rotating disc 26 to cause the flange 24 to expand into rifling 5 of mortar tube 2. A portion of the gas pressure is bled into the spigot tube 6 through the strainer 15 for separating purposes between the projectile 13 and mortar tube 2. The main portion of the gas pressure generated is against the expander plate 26 forcing the anti-spin device 9 against the spigot tube 6 and the projectile 13 forward. Because of the relatively high moments of inertia of the mass ahead of the Teflon slip disc 21 and sleeve 22 and the cap 11 of the spigot tube 6, the rotating disc 23 and the expander plate 26 will follow the rifling 5 down the mortar tube 2 without imparting any appreciable torque to the cap 11 and spigot tube 6.

It is to be understood that the form of the invention herewith shown and described, is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention, or the scope of the subjoined claims.

What is claimed is:

1. In combination with a projectile to be fired from a weapon barrel having rifling therein, said projectile including a warhead, a spigot tube having a rearwardly extending, tubular strainer and a rearwardly disposed propelling charge; an anti-spin device for reducing the torque normally applied to said projectile by said rifling, said anti-spin device comprising, an anti-friction slip-disc defining a disc shaped body portion and an axially disposed, rearwardly extending tubular portion integral with said body portion, said tubular portion being rotatably mounted on said tubular strainer, and said slip-disc being in abutting relation with said spigot tube, an obturating member rotatably mounted on the tubular portion of said slip-disc and abutting said slip-disc and a pressure plate slidable on the tubular portion of said antifriction slip-disc whereby when said plate is moved forward upon pressure of combustion gases, it Will expand said obturating member and engage said rifling whereby said antifriction member and said obturating member will follow said rifiing down said barrel.

'1 n 4 2. A device as set forth in claim 1 wherein said oh- References Cited by the Examiner turating member comprises a disc having a central open- UNITED STATES PATENTS ing and rearwardly extending annular flange along its outer circumference thereof, said flange being beveled $2235 along its inner peripheral surface. 5 290O873 8/59 Wust 3. A device as set forth in claim 1 wherein said pressure plate comprises a disc having a central opening and BENJAMIN BORCHELT, Primary Examinera bevel along its outer circumference thereof. SAMUEL W. ENGLE, Examiner. 

1. IN COMBINATION WITH A PROJECTILE TO BE FIRED FROM A WEAPON BARREL HAVING RIFLING THEREIN, SAID PROJECTILE INCLUDING A WARHEAD, A SPIGOT TUBE HAVING A REARWARDLY EXTENDING, TUBULAR STRAINER AND A REARWARDLY DISPOSED PROPELLING CHARGE; AN ANTI-SPIN DEVICE FOR REDUCING THE TORQUE NORMALLY APPLIED TO SAID PROJECTILE BY SAID RIFLING, SAID ANTI-SPIN DEVICE COMPRISING, AN ANTI-FRICTION SLIP-DISC DEFINING A DISC SHAPED BODY PORTION AND AN AXIALLY DISPOSED, REARWARDLY EXTENDING TUBULAR PORTION INTEGRAL WITH SAID BODY PORTION, SAID TUBULAR PORTION BEING ROTATABLY MOUNTED ON SAID TUBULAR STRAINER, AND SAID SLIP-DISC BEING IN ABUTTING RELATION WITH SAID SPIGOT TUBE, AN OBTURATING MEMBER ROTATBLY MOUNTED ON THE TUBULAR PORTION OF SAID SLIP-DISC AND ABUTTING SAID SLIP-DISC AND A PRESSURE PLATE SLIDABLE ON THE TUBULAR PORTION OF SAID ANTI- 